1. Field of the Invention
The present invention relates to a method of manufacturing an electronic device and more particularly to a method of manufacturing an electronic device having a buried multilayer wiring structure.
2. Description of the Background Art
In a method of manufacturing a semiconductor device having a buried multilayer wiring structure, recently, there has been employed a technique referred to as a dual-damascene method in order to electrically connect a structure of lower layers provided by interposing an interlayer dielectric film therebetween to an upper wiring. In this technique, a plug reaching the structure of the lower layers through the interlayer dielectric film and the upper wiring are formed at the same time. An example of this method has been disclosed in Japanese Patent Application Laid-Open No. 2000-269326 (Column 4, FIGS. 1 to 8) (which will be hereinafter referred to as Patent Document).
More specifically, the Patent Document has disclosed an example in which a resist material is buried in a contact hole reaching a semiconductor substrate through an interlayer dielectric film and ultraviolet rays are irradiated on the resist material to be cured, and a wiring trench for forming an upper wiring is provided in a surface of the interlayer dielectric film by etching.
In a recent method of manufacturing a semiconductor device, a KrF excimer laser having a wavelength of 248 nm and an ArF excimer laser having a wavelength of 193 nm are used for an exposing light source in order to form a fine resist pattern having a line width of 0.3 μm or less and a chemically amplified resist utilizing a catalytic reaction is used for a resist material to be a sensitizer in many cases.
The chemically amplified resist has a mechanism for generating a hydrogen ion by sensitization and using the hydrogen ion as a catalyst to thermally react a resist resin, thereby resolving a pattern. In the case in which the chemically amplified resist is used, there is a possibility that a so-called resist poisoning phenomenon might present itself, because of a neutralization of a hydrogen ion, that is, a wiring pattern connected to an outermost hole of a hole pattern, particularly, an isolated hole pattern or a densely disposed hole pattern might not be resolved normally.